JP3420781B2 - Solar power transmission equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits collected solar energy to a target object as a power receiving object such as a ground, a flying object, a space station or a space factory by using microwaves. The present invention relates to a power transmission device for solar power generation. 2. Description of the Related Art Solar power generation is, for example, July 14, 1992.
The one published on the 15th page of the 13th edition of the Yomiuri Shimbun (Morning Edition) has been proposed. This is as shown in FIG. In FIG. 6, a solar power satellite 101 launched into a geosynchronous orbit from the earth as a power generation device collects solar energy, converts the solar energy into microwaves, and sends the microwaves from a target object (not shown). The electric power is transmitted from the solar power satellite 101 to the target object by transmitting the pilot signal in the direction of arrival. [0003] Incidentally, a power transmitting apparatus for solar power generation is a phased array antenna system for controlling the phase of a microwave as a transmitted radio wave and transmitting the microwave in the same direction as the arrival direction of a pilot signal. A retro-directive approach has been attempted. The retro-directive method will be described. In FIG. 7, a target point at which transmission radio waves are to be concentrated is assumed to be A, and a frequency ω
_i becomes the pilot signal is radiated, receives the pilot signal at each antenna element of the power transmission, it is assumed that the transmission wave of frequency omega _t is radiated toward the target point A. At this time, assuming that the transmitted radio wave emitted from the target point A reaches the center (reference point) P ₀ on the power transmission side at a distance X ₀ after the time t, the phase of the pilot signal at the reference point P ₀ is , Φ ₀ = ω _i (t ₀ −X ₀ / C) (1) Here, C is the speed of light. Similarly, the phase at one point P ₁ on the power transmission side that is a distance X ₁ away from the target point A is represented by φ ₁ = ω _i (t ₀ −X ₁ / C) (2). Phase difference between two points in this _{case, Φ i = φ 1 -φ 0} = -ω i r / C ......... it becomes (3). Here, r = X ₁ −X ₀ . [0004] Assuming that transmitted waves are radiated in the same phase at the points P ₀ and P ₁ , the phase difference at the target point A is given by the following equation (3) since the transmitted wave frequency is ω _{t. t} = _{-ω t} r / C ......... it is (4). Therefore, to the power transmission wave phase from two points P _0, P ₁ is equal at the target point A, the _{Φ c = ω t r / C} ......... (5) may'll be compensated in _one point P. Therefore, by performing the phase compensation of equation (5) at each point on the power transmission side,
The phases of all transmitted radio waves emitted from the power transmission side become equal at the target point A. This is the principle of the retrodirective system. [0005] The adoption of this retrodirective system in a power transmission device for solar power generation requires an enormous amount and weight if all power transmitting antenna elements are provided with a pilot power receiving system and a phase conjugate circuit required for the retrodirective system. For this reason, the power transmitting antenna element is divided into several sub-array blocks, and each sub-array has one pilot power receiving system and one phase conjugate circuit. The transmission power is supplied to the power transmitting antenna elements in each sub-array in the same phase. Also, in the retrodirective method, a pilot signal is emitted from the target object side, but since the microwave has high power, if the frequency of the pilot signal is the same as the frequency of the microwave on the power transmission side, the pilot signal is extracted. It becomes difficult to do. For this reason, in a power transmission device for solar power generation, for example, Mitsubishi Electric Corporation has proposed an asymmetric dual-frequency system as shown in "Beam Control Power of Microwave Power Transmission Antenna" (Basic Experiment on Space Station in 1988) Research report: According to the item "Development of microwave wireless energy transmission system" in the Space Utilization Research Committee of ISAS. The phase conjugate circuit 110 of the asymmetric two-frequency retrodirective system is as shown in FIG. In FIG. 8, a demultiplexer 111 demultiplexes a pilot signal having a phase θ ₁ (t) and a pilot signal having a phase θ ₂ (t) received by a pilot antenna on the solar power generation satellite side. The −1 multiplier 112 multiplies the output of θ ₁ (t) demultiplexed by the demultiplexer 111 by −1. The doubler 113 is
The output of θ ₂ (t) split by the splitter 111 is doubled. The first mixer 114, mixed with two signals with doubled output of 2 [Theta] ₂ (t) from - [theta] ₁ -1 multiplier output and doubler 113 (t) from -1 multiplier 112 Then, the signal is output to the first bandpass filter 115. The bandpass filter 115 outputs any one of the sum signal and the difference signal mixed by the first mixer 114 to the second mixer 116. The second mixer 116 is connected to the transmitter 1
A local signal having a frequency different from that of the pilot signal from the frequency of the pilot signal and an output signal from the band-pass filter 115 are mixed and passed through a second band-pass filter 118,
The signal θ _t (t) is output to the power transmitting antenna side of the solar power satellite. [0007] In the above-described microwave system for solar power generation, a beam control system based on a retrodirective system in units of sub-arrays is employed. In this method, the microwave beam can be scanned only within the directivity range of the sub-array. In order to scan the microwave beam over a wide range of angles, the sub-arrays must be smaller and each sub-array must have a conjugate circuit for retro-directives. At present, a conjugate circuit having no error is based on the asymmetric two-frequency method described above. However, the circuit system is complicated because two frequencies are used, and it is impractical to combine a conjugate circuit of the two-frequency method with each antenna element. It is. Here, an object is to realize a power transmission system that scans a wide angle range with a simple system without errors. According to the present invention, solar energy collected by a power generation unit is converted into electric energy, this electric energy is converted into microwaves, and the phase of the microwaves is used as a power receiving object. In a solar power transmission device that controls by the pilot signal sent from the target object and transmits the microwave in the direction of arrival of the pilot signal, a phase conjugate circuit that multiplies the input pilot signal by n,
A demultiplexing circuit for demultiplexing the signal output from the phase conjugate circuit into the number of power transmitting antenna elements, an angle detection circuit for detecting an arrival direction of the pilot signal, and the microwave from the signal output from the angle detection circuit. An arithmetic processing unit for calculating a power supply phase difference of a power transmitting antenna focused on the target object, and a variable phase shift circuit for generating a phase difference in a signal output from the demultiplexing circuit by a signal output from the arithmetic processing unit And a power amplifier that amplifies the electric energy to electric energy for microwave transmission having a phase difference based on a signal output from the variable phase shift circuit; and the input pilot signal provided in the phase conjugate circuit. Means for obtaining a difference signal by a common pilot signal serving as a power transmission reference point in the pilot signal. The collected solar energy is converted into electric energy, and the electric energy is converted into microwaves. on the other hand,
A difference signal is obtained by a pilot signal sent from a target object as a power receiving object and a common pilot signal serving as a power transmission reference point in the pilot signal. The pilot signal is multiplied by n, and the n-multiplied signal is demultiplexed into the number of power transmitting antenna elements. Further, the direction of arrival of the pilot signal is detected, and from this angle detection signal, a feeding phase difference of the power transmitting antenna in which the microwave is focused on the target object is calculated. Cause. Then, the electric energy is amplified to microwave transmission electric energy having a phase difference based on the variable phase shift signal. The microwave is transmitted in the direction of arrival of the pilot signal by the amplified electric energy. FIG. 1 shows an embodiment of a power transmission device for solar power generation. In FIG. 1, four pilot antennas 1, 2, 3, and 4 for receiving a pilot signal emitted from a target object (not shown) are provided for a subarray in which one power transmitting antenna is divided into blocks. . One of the four pilot antennas 1 to 4 outputs the received pilot signal of, for example, 8 GHz to the phase conjugate circuit 6 via the receiving circuit 5. The phase conjugation circuit 6 multiplies the inputted pilot signal by n and outputs it to the demultiplexing circuit 7. The demultiplexing circuit 7 demultiplexes the input pilot signal to generate a plurality of variable phase shifters 8a, 8b,
.., 8n. On the other hand, the remaining three pilot antennas 3, 4, and 5 are arranged at three points, and receive the received pilot signals via receiving circuits 9, 10, and 11, respectively.
It outputs to the angle detection circuit 12 comprised in the F interferometer. The angle detection circuit 12 determines the direction of the target object by measuring the phase difference between the pilot signals received by the three pilot antennas 2 to 4, and calculates the angle signal indicating the direction of the target object by an arithmetic processing unit configured in a microcomputer. 13 is output. The arithmetic processing unit 13 uses the angle signal input from the angle detection circuit 12 to transmit the power transmission antenna 1 of the solar power generation satellite.
5, transmitting antenna elements 15a, 15b,...
The microwave output from 15n is focused on the power receiving antenna of the target object to calculate the feeding phase difference on the sub-array of the power transmitting antenna, and to the variable phase shifters 8a, 8b,. Output. Variable phase shifter 8
a, 8b,..., 8n generate a phase difference in the signal input from the demultiplexing circuit 7 based on the power supply phase difference signal input from the arithmetic processing unit 13 to generate a plurality of power amplifiers 14a, 14a.
b,..., 14n. Power amplifiers 14a, 14
b,..., 14n amplify the power output from the power generation unit 16 of the solar power satellite, the microwaves output from the variable phase shifters 8a, 8b,. Output to the antennas 15a, 15b,..., 15n.
The power transmitting antennas 15a, 15b,..., 15n radiate, for example, a 24 GHz microwave having a power supply phase difference from the power amplifiers 14a, 14b,. Further, a plurality of variable phase shifters 8
, 8n and a plurality of power amplifiers 14a, 14a
.., 14n are the transmitting antenna elements 15a, 15
.., 15n are arranged one by one.
The receiving circuit 5, the phase conjugate circuit 5, the demultiplexing circuit 7, and the variable phase shift circuits 8a, 8b,..., 8n constitute a phase control unit 17. Also, three pilot antennas 2,
3, 4 and three receiving circuits 9, 10, 11; one angle detecting circuit 12 and one arithmetic processing unit 13;
8. FIG. 2 shows the phase conjugate circuit 6 described above. In FIG. 2, a mixer 20 forms a doubler 21 from a pilot signal received by one pilot antenna 1 shown in FIG. 1 and a pilot signal received by a pilot antenna (not shown) located at a reference point on the power transmission side. The difference signal from the pilot signal, which is a common reference position signal generated by passing through, is output to the band-pass filter 22. The band pass filter 22 converts only the difference signal, that is, the conjugate phase component from the sum signal and the difference signal output from the mixer 20 into a tripler 23
Output to The tripler 23 multiplies the input conjugate phase component by three, and outputs a signal of a triple frequency whose phase is conjugate to the pilot signal to the demultiplexer 7 shown in FIG. That is, the phase conjugate circuit 6 performs the phase compensation by the retrodirective method. Specifically, in the above-described retrodirective method, the phase ω _i t of the input signal at the transmission-side reference point P ₀
When, at point P _1, the more the above-mentioned _{(3), ψ = ω i t-ω} i r r / C = ω i (t-r / C) ......... (6). The output signal of the phase after compensating for the phase at the point P ₁ is not become the above-mentioned (5) from _{equation, ψ = ω t t + ω} t r / C = ω t (t + r / C) ......... (7) Must. Therefore, the phase conjugate circuit 6
Changes the input signal of equation (6) to the output signal of equation (7). FIG. 3 shows the angle detection circuit 12. In FIG. 3, the angle detection circuit 12 is a 3
Three bandpass filters 30, 31, 32 corresponding to the two pilot antennas 2 to 4, and three preamplifiers 3
3, 34, 35 and three phase detectors 36, 37, 38
And detects the phase difference between the pilot signals input to the three pilot antennas 2 to 4 and outputs the same to the arithmetic processing unit 13 shown in FIG. The principle of the angle detection circuit 13 is to determine the angle of arrival of the radio wave by measuring the phase difference between the radio waves entering the antenna at two points on the base line. That is, in FIG. 4, if the phase difference is ψ, AB is the baseline, S is the target, R, a, b, and D are the illustrated distances and λ is the wavelength, ψ = 2π (ab) / λ. ... (8) b ² = (D / 2) ² + R ² −DR cos θ a ² = (D / 2) ² + R ² −DR cos θ a ² −b ² = ² DR cos θ a−b = D cos θ {2R / (a + b)} ... (9) Here, if R> D and b is almost equal to R (2R = a + b), then a−b = Dcos θ. Therefore, cos θ = (ab) / D = ψλ / 2πD (10) Therefore, if the base line length D is known, the wavelength is known, and the angle θ of the radio wave arrival direction can be measured. FIG. 5 shows the phase correction in the arithmetic processing unit 13. In FIG. 5, an arithmetic processing unit 13 includes an arrival direction θ of the pilot signal obtained by the angle detection circuit 12.
, Compensates the phase difference dsinθ for each antenna element,
The phases of microwaves to be transmitted are aligned at the power receiving antenna of the target object. Therefore, according to this embodiment, three pilot antennas 2, 3, 4 and three receiving circuits 9, 1 are provided.
, 15 by the signal processing unit 18 and the phase conjugate circuit 6 including the first and second angle detection circuits 12 and one arithmetic processing unit 13.
Since the phase is controlled every n, the phase of all the radio waves emitted from the power transmitting antenna elements 15a, 15b,. Since the light is focused on the power receiving antenna in the same phase, the power receiving efficiency is improved. Further, according to this embodiment, the phase conjugate circuit 6 includes a pilot signal input from one pilot antenna 1 and a common pilot input from a pilot antenna (not shown) located at a reference point on the power transmission side. Since a difference signal is obtained by using a signal, a local signal is not required. Therefore, an oscillator is not required on the power transmission side, and the structure is simplified. Further, according to this embodiment, since the frequency of the pilot signal is 1 / n of the frequency of the microwave and only the unmodulated pilot signal is received, the receiving circuits 5, 9 and 10 and 11 can be constituted only by a series circuit of a band-pass filter and an amplifier, and the structure is simplified. Further, according to this embodiment, the structures of the phase conjugate circuit 6 and the receiving circuits 5, 9, 10, 11 are simplified, so that the weight is reduced. According to the present invention, the phase is controlled for each power transmitting antenna element by the angle detection circuit, the arithmetic processing unit, and the phase conjugate circuit. Even when the distance is close to a certain degree or more, for example, about several kilometers, the phase of all radio waves emitted from the power transmitting antenna element can be focused on the power receiving antenna of the target object in the same phase, thereby improving the power receiving efficiency. it can. Further, the phase conjugate circuit includes means for obtaining a difference signal by a pilot signal input from one pilot antenna and a common pilot signal input from a pilot antenna (not shown) located at a reference point on the power transmission side. Therefore, no local signal is required, and therefore, no oscillator is required on the power transmission side, the structure can be simplified, and the size and weight can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing one embodiment of a power transmission device for solar power generation. FIG. 2 is a conjugate circuit diagram of one embodiment. FIG. 3 is an angle detection circuit diagram of one embodiment. FIG. 4 is a diagram illustrating the principle of an astronomical interferometer according to one embodiment. FIG. 5 is a view for explaining phase correction in an arithmetic processing unit according to one embodiment. FIG. 6 is a perspective view showing a solar power generation satellite. FIG. 7 is a diagram showing a retrodirective system of a conventional solar power transmission device. FIG. 8 is a diagram of a conventional asymmetric two-frequency phase conjugate circuit. [Description of Signs] 6 ... Phase conjugate circuit 7 ... Demultiplexing circuits 8a, 8b, ..., 8n ... Variable phase shift circuit 12 ... Angle detection circuit 13 ... Operation processing units 14a, 14b, ..., 14n ... Power amplifier 16 ... Power generation Unit 17: Phase control unit 18: Signal processing unit 21: Combiner

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jiro Kawachiyama 2-5-5 Shiba-Daimon, Minato-ku, Tokyo Inside the Rocket System Co., Ltd. (72) Inventor Teruo Fujiwara 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. (72) Inventor Hidemi Yasui 2 Takaracho, Kanagawa-ku, Yokohama City, Kanagawa Prefecture Nissan Motor Co., Ltd. Hiroyuki 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. (56) References JP-A-4-112635 (JP, A) JP-A-57-97704 (JP, A) JP-A-3-11562 ( JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02J 17/00 H01Q 3/26-3/42 H04B 1/18

Claims (1)

(57) [Claims 1] The solar energy collected by the power generation unit is converted into electric energy, the electric energy is converted into microwaves, and the phase of the microwaves is converted into a target object as a power receiving object. In the solar power transmission device that controls the microwaves in the direction of arrival of the pilot signal by controlling the pilot signal sent from the controller, a phase conjugate circuit that multiplies the input pilot signal by n, and an output from the phase conjugate circuit A branching circuit that branches the obtained signal into the number of power transmitting antenna elements, an angle detection circuit that detects an arrival direction of the pilot signal, and the microwave focused on the target object from a signal output from the angle detection circuit. An arithmetic processing unit for calculating a power supply phase difference of the power transmitting antenna to be transmitted; and a signal output from the arithmetic processing unit, A variable phase shift circuit for generating a phase difference in the output signal; a power amplifier for amplifying the electric energy to microwave transmission electric energy having a phase difference based on the signal output from the variable phase shift circuit; Means for providing a difference signal based on the input pilot signal and a common pilot signal serving as a power transmission reference point in the pilot signal provided in the conjugate circuit, comprising: